Comments
Patch
@@ -206,6 +206,7 @@ passive
passive trip point for the zone. Activation is done by polling with
an interval of 1 second.
Unit: millidegrees Celsius
+ Valid values: 0 (disabled) or greater than 1000
RW, Optional
*****************************
@@ -225,6 +225,12 @@ passive_store(struct device *dev, struct device_attribute *attr,
if (!sscanf(buf, "%d\n", &state))
return -EINVAL;
+ /* sanity check: values below 1000 millicelcius don't make sense
+ * and can cause the system to go into a thermal heart attack
+ */
+ if (state && state < 1000)
+ return -EINVAL;
+
if (state && !tz->forced_passive) {
mutex_lock(&thermal_list_lock);
list_for_each_entry(cdev, &thermal_cdev_list, node) {
Values below 1000 milli-celsius don't make sense and can cause the system to go into a thermal heart attack: the actual temperature will always be lower and thus the system will be throttled down to its lowest setting. An additional problem is that values below 1000 will show as 0 in /proc/acpi/thermal/TZx/trip_points:passive. cat passive 0 echo -n 90 >passive bash: echo: write error: Invalid argument echo -n 90000 >passive cat passive 90000 Signed-off-by: Frans Pop <elendil@planet.nl> Cc: Matthew Garrett <mjg@redhat.com> Cc: Zhang Rui <rui.zhang@intel.com> --- Documentation/thermal/sysfs-api.txt | 1 + drivers/thermal/thermal_sys.c | 6 ++++++ 2 files changed, 7 insertions(+), 0 deletions(-)